Find your size

Bra size calculator

Two measurements and one subtraction. Enter them below and we'll do the maths. Sizes follow the Indian convention, where your band is your underbust measurement plus four inches.

Measure in
Snug and level, breathing out.
Around the fullest part, tape level.
Two measurements

How to measure your bra size at home

01
Measure your underbust
Run the tape right under your bust, snug and level the whole way round. Breathe out before you read it. This number decides your band, and the band is what actually holds a bra up.
02
Measure your bust
Tape across the fullest part, level front to back, resting rather than pulling. Wear a soft unpadded bra or nothing at all. Pulling the tape tight here is the most common reason a calculated cup comes out a size too small.
03
Do the subtraction
Round the underbust up to the next even number and add four. That is your band. Subtract the band from your bust, and count each inch as one cup letter starting at A: one inch is A, two is B, three is C.
Sizing questions

Questions people ask about bra size

Which cup is bigger, B, C or D?

D, then C, then B, but only at the same band size. A cup letter is not a fixed volume. It is the gap between your bust and your band, so a C on a 42 band holds considerably more than a C on a 30 band.

Is 34 or 36 a bigger bra size?

36 has the bigger band. On Indian sizing that number is your underbust plus four, so a 36 suits roughly a 31 to 32 inch underbust and a 34 suits 29 to 30.

Is 34C or 36C bigger?

36C. Same letter, larger band, and the cup scales up with the band, so a 36C holds roughly what a 34D does.

How do I calculate my bra size?

Round your underbust up to an even number and add four for the band. Subtract the band from your bust, and each inch is one cup letter starting at A. That is the whole calculation.

What if I fall between two sizes?

Go by the band first, because the band carries the support. If your underbust lands between two even numbers, take the smaller band and the next cup letter up. A snug band that stays level is what stops a bra riding up at the back.